NASAs Curiosity rover touched down on Mars in August 2012, and its been cruising around, shooting lasers at rocks, drilling into the ground, and performing science experiments ever since. Just last week, news came out that Curiosity had found something salty. The rover is driving across Gale Crater, an ancient Martian lake bed that was once filled with water, and has discovered sulfate salts.
Scientists think this is likely due to a very dry period when water evaporated, leaving the salts behind. Our own Earth stays wet because we have an atmosphere and a magnetic field, which keeps our planet watery and healthy so we can comfortably survive. But the story for Mars is a bit more complex. Billions of years ago, Mars had an atmosphere but its always had a rather small magnetic field, so the solar winds from the Sun stripped the atmosphere away over timeleaving it the dry, arid planet we have grown to love.
This week were going to rove around on Mars alongside the biggest, baddest, robot on the red planet.